This American icon of masculinity and patriotism eventually appeared in more than 175 movies. He won an Academy Award for his portrayal of crusty Rooster Cogburn in True Grit. He played dozens of cowboys in a wealth of Westerns, and was Maureen O’Hara’s Quiet Man. If you remember an old war movie, it probably starred the Duke.

How did this thrice-married, hard-drinking, larger-than-life megastar make his leap to Catholicism? Faith danced around John Wayne all of his adult life. All three of his wives had been raised Catholic, and all seven of his children were brought up in the Church. His first wife, Josie, who prayed for Duke’s conversion till the end, convinced him to attend numerous parish events with her. He sometimes complained to friends that he was up to his neck in Catholics, but perhaps as he interacted with genuine, faithful people, misconceptions and prejudices fell away. Did the classic church potluck plant seeds of conversion?

Despite his early upbringing in the Presbyterian Church, Duke never had any denominational loyalty and was impatient with the infighting of Christianity. Wayne’s son Michael thought his father was a man who quietly believed in God even as he shunned church attendance. “There must be a higher power,” Wayne said in the year he died, “or how does all this stuff work?”

Catholic priest Fr. Matthew Muñoz, who knew Wayne simply as “Granddaddy,” hints that obstacles to his grandfather’s conversion toppled slowly as Wayne grew in knowledge of Catholicism. “After a while,” Fr. Muñoz said, “he kind of got a sense that the common secular vision of what Catholics are and what his own experience actually was were becoming two greatly different things.”

In the mid-1960s, Duke was fighting a persistent cough. His wife urged him to have it checked, and since he needed to renew an insurance policy anyway, he had a physical. When he returned to the clinic the next day for results, he was subjected to an extensive round of X-rays. As he waited, he ran into the technician who’d performed the tests. The young tech revealed what he thought the star already knew: it was lung cancer.

John Wayne, whom the whole world saw as invincible, beat the lung cancer, as everyone knew he would. He became a vocal advocate for those fighting the disease, and his family eventually established the John Wayne Cancer Institute.

Then in 1974, when the star began battling repeated respiratory illnesses, he feared that the lung cancer had returned, but the doctors told him not to worry. Symptoms of seemingly unrelated illnesses plagued him over the next few years until finally, in 1978, an accurate diagnosis was made. John Wayne had stomach cancer. He deteriorated quickly. By the following year, he was extremely sick, wasting away, and often hospitalized.

Wayne had watched his friend John Ford suffer from the same kind of cancer just a few years before. Ford had been a Catholic; he died with priests in the room and a rosary in his hand. Ford’s faith and its uplifting effect on his life and death were etched into Wayne’s psyche. Duke remembered the comfort and courage Catholicism had given his friend.

Read the complete conversion story of John Wayne, Oscar Wilde, Gary Gooper and more.

On May 14, 1979, Michael asked his father if it would be okay to have Archbishop Marcos McGrath come and visit. Duke said yes, and the two men spent an afternoon together talking. Wayne agreed that day to call for a priest before he died. Duke had often joked with his family that he was a “cardiac Catholic,” that at the last minute he’d call in a priest. Now he made that promise.

With the end near, Wayne was in constant agony.

Two days before he died, Wayne, in tremendous pain, agreed when his son Patrick asked him if they should call the priest now. “Yeah,” Duke said, “I think that’s a good idea.” Fr. Robert Curtis, UCLA Medical Center chaplain, arrived. He baptized the dying man, probably conditionally, as Wayne had grown up in a Christian church, and administered last rites. That night, Wayne fell into a coma. “I don’t know the technicalities of the Church or what constitutes a conversion,” said Michael. “But Dad did die in the Church.”

Karen Edmisten is a convert to the Catholic Faith and the author of several books including "After Miscarriage: A Catholic Woman's Companion to Healing and Hope."